Boks expect the unexpected from 'evolving' All Blacks

South Africa are bracing themselves for "new tricks" from defending champions New Zealand when the fierce rivals lock horns in their heavyweight Rugby World Cup opener this weekend.

Assistant coach Matt Proudfoot said Tuesday that the Springboks expect the All Blacks to come out firing in the Pool B clash in Yokohama after the southern hemisphere titans battled to a 16-16 draw over the summer during the Rugby Championship.

South Africa won that competition for the first time since 2009 to underline their World Cup credentials, but Proudfoot suspects New Zealand are planning a surprise or two this Saturday.

"We're expecting a new arrow to their quiver," he said before a training session in the shadow of Tokyo Disneyland.

"They're an intelligent bunch and there will be something new that they bring to the party.

"They have been working on various aspects of their attack," added Proudfoot.

"There's been quite a bit of evolution in that area of their game. And they're too good a side not to continue their evolution."

South Africa famously beat New Zealand on home soil to capture the first of their two World Cups in 1995, when Nelson Mandela presented the trophy to Springbok captain Francois Pienaar in an iconic moment that helped heal a nation divided by decades of apartheid.

Though less politically charged than that spine-tingling Johannesburg final, victory in this weekend's blockbuster could have huge psychological importance for the rest of the tournament before further pool games against Italy, Namibia and Canada.

- Mind games -

"It's not ideal to start a competition on the back foot," admitted Proudfoot.

"Both teams understand that. Our mindset in 2019 has been to generate a lot of momentum which we have attained and it will be good to keep that momentum going," added the forwards coach.

"But I don't think if you win this game all of a sudden you're hot favourites for the tournament either."

With the All Blacks sweating over the fitness of lock Brodie Retallick, Proudfoot accused New Zealand head coach Steve Hansen of indulging in mind games in the build-up to the game.

"Mr Hansen said he had a full squad to pick from," he smiled. "I wouldn't be surprised if he doesn't have a trick up his sleeve."

South Africa, who reached the World Cup semi-finals in 2015 despite a stunning loss to Japan in their opening game, have just returned from a heat camp in Kagoshima, southern Japan, where several players shed kilos in weight.

While tighthead prop Frans Malherbe joked that some of the forwards could do with shedding a few pounds, centre Damian de Allende can't wait to go at it with opposite number Sonny Bill Williams.

"He poses a big threat with his offloading game," he said.

"He's very strong and very powerful in contact too, but the last few games we've managed to put him under pressure. The challenge he gives you is amazing, I love it. If you embrace that challenge, it can only make you a better rugby player."